Forty years ago, a caravan of more than 50 cars full of demonstrators pulled into Pine Ridge Reservation in South Dakota. That day marked the beginning of a 71-day occupation led by members of the Oglala Lakota tribe and followers of the American Indian Movement, attempting to address long-standing grievances — not only with the U.S. government but also with tribal leaders.

Over those 71 days, Pine Ridge was effectively barricaded from the outside world. Electricity was turned off even though it was winter, and food and medical supplies were halted. Two Native Americans and one FBI agent died before the standoff ended.

A young Owen Luck got there on the fourth day. He had been a medic in the Vietnam War and was a fledgling photojournalist. "I had very little experience, and this would be considered my first shoot," he says.